My Microsoft Wireless Optical Desktop for Bluetooth Keyboard works (I
am typing this on the keyboard) without a passkey, but I cannot get it
to setup with a security passkey. When I accept the option to set it
up without the passkey, it connects with no problem. When I try to
set it up with a passkey, it assigns a passkey number and attempts
unsuccessfully to make a connection. The keyboard previously worked
with a passkey, but recently lost its connection. It was when I tried
to reestablish the connection that the problem developed. The
Bluetooth wireless mouse functions properly. Any suggestions would be
appreciated.

Also, what is the real world security risk of using the keyboard
without a passkey.

Thank you.